Chimera Mission Recommendations

I've recently had enough free time open up to finally start down the Chimera set of personal missions. The grind was pretty frustrating but surprisingly fast considering I only am able to play for a few hours a night after work.

As of right now I have Union 15 done without honors thanks to the big head of the ST-I, Alliance 15 ready to begin, and the only thing holding me back from starting the other two are the top gun missions.

I need to get two top guns for Bloc and one for Coalition. Been stuck here for about a week now and I'm starting to get frustrated. STB-1, E75, and AMX 30 have been my go tos while I try to grind out the rest of the Czech TD mission while also attempting to accomplish those three. Does anyone have any recommendations for tanks to try that I may be missing? Been to five kills a few times now but either the team rolls the other flank before I arrive, RNG tells me I'm not allowed to pen the kill shot, or I'm at a point of my session where I'm so tilted that I do something stupid and end up dying instead – like last night I yoloed a 3/4 health Type 61 in my STB-1 because I had full health, only to find out he had an unspotted friend and lost my DPM because I was ammo racked twice in a row. RIP top gun.

I have the AMX 13 57 but it's maxed out on battle pass points so I have to avoid using it until I have the TVP 100.

Thanks in advance!